Spoof Surface Plasmon based Planar THz Sensor System using Dumbbell Shaped Unit Cell

A spoof surface plasmon polariton (SSPP) transmission line based THz sensor using a perforated dumbbell shaped unit cell is presented. The proposed SSPP structure possesses better confinement ability as compared to the conventional microstrip line in the THz frequency regime which actually helps to realize the THz sensor with improved sensitivity. The designed SSPPs based structure is having under layer ground in order to obtain better conversion between conventional microstrip to SSPP structure due to efficient impedance matching between them in the microwave and THz frequency band. To design the THz dielectric sensor using the proposed highly confined SSPP transmission an appropriate capacitive slot on the dumbbell cells is created. Design and optimization of the proposed SSPP based resonant structure is performed using the CST-MWS in the THz and microwave frequency range. Thereafter, a prototype of the resonant SSPP (scaled for microwave region) sensor is fabricated and accordingly the shift in the resonance frequency is measured after loading the sensor with the test specimen.